Various roller skates emerge as the roller skating becomes popular. In order to provide the roller skating fans with a kind of shoes for both walking and skating, the so-called “Gustily Walking Shoes” appears on the market, which comprises in-line wheels at the heel, the wheels being in a same plane as the sole. The wearer can walk as usual, and skate by lifting the tiptoe on the ground suitable for roller skating. Although such Gustily Walking Shoes have both functions of walking and skating, the wearer must lift the front sole of the foot while straining at the heel during skating, unable to skate easily with normal posture.
The patent patents CN2481375Y, CN2456777Y and US2002/0163143A1 also disclose some roller skates having retractable wheels. Such shoes are characterized in that the sole comprises a recess for receiving the wheels which can be stretched out of or folded in the recess, thereby achieving both functions of skating and walking. Nevertheless, the wheels are still received inside the recess of the shoe sole when not in use and thus burden the user during walking. In addition, since the wheels have to be received at an underside of the shoe, the diameter of the wheel will be limited such that the speedy and laborsaving effect during skating will be watered down.
The patent U.S. Pat. No. 6,344,621B1 also discloses a roller skate, which becomes a roller skate by engaging the sole and wheel portion through a threaded joint member, or becomes shoes for normal walking by loosening the threaded joint member. The drawback of such shoes is that the threaded engagement requires particular tools and the wheels can not be freely attached and detached during wearing, which leads to inconvenience of use.